feat : 문제 생성 시 잘못된 링크 예외 조건 추가 (#190)

* feat : 문제 생성 시 잘못된 링크 예외 조건 추가

* feat : parts 크기 조건 수정

src/main/java/com/gamzabat/algohub/constants/ApiConstants.java

@@ -3,6 +3,7 @@
 public final class ApiConstants {
 	public static final String SOLVED_AC_PROBLEM_API_URL = "https://solved.ac/api/v3/problem/lookup?problemIds=";
 	public static final String BOJ_USER_PROFILE_URL = "https://www.acmicpc.net/user/";
+	public static final String BOJ_PROBLEM_URL = "www.acmicpc.net";
 
 	private ApiConstants() {
 		throw new RuntimeException("Can not instantiate : ApiConstants");

src/main/java/com/gamzabat/algohub/feature/problem/service/ProblemService.java

@@ -337,7 +337,7 @@ private String getProblemTitle(JsonNode problemDetails) {
 	private String getProblemId(CreateProblemRequest request) {
 		String url = request.link();
 		String[] parts = url.split("/");
-		if (!parts[2].equals("www.acmicpc.net"))
+		if (parts.length < 3 || !parts[2].equals(BOJ_PROBLEM_URL))
 			throw new NotBojLinkException(HttpStatus.BAD_REQUEST.value(), "백준 링크가 아닙니다");
 		return parts[parts.length - 1];
 	}